The present invention relates to a silver halide color photographic lightsensitive material containing a coupler which releases a photographically useful group or its precursor (hereinafter may be simply referred to as "photographically useful group-releasing coupler"). More particularly, the present invention relates to a silver halide color photographic light-sensitive material containing a novel photographically useful group-releasing coupler that is capable of forming a cyclization product along with releasing a photographically useful group or its precursor by an intramolecular nucleophilic substitution reaction effected by a nitrogen atom of a coupling product that is produced by a reaction of the coupler with a developing agent in an oxidized form, the nitrogen atom originated from the developing agent and directly bonded to the coupling position of the coupler.
In the field of color photographic lightsensitive materials, it is known that the performance of photographic image is markedly enhanced by releasing a photographically useful group in a silver image-wise manner simultaneously with the formation of silver image.
For example, a DIR coupler exerts the effects, such as the enhancement of the graininess of color image, the enhancement of sharpness through edge effect and the enhancement of color reproducibility through the diffusion of inhibitor to another layer, by releasing a development inhibitor through a coupling reaction with a developing agent in an oxidized form at the time of development. These are described in detail in, for example, U.S. Pat. (hereinafter referred to as "U.S. Pat.") No. 4,248,962 and Jpn. Pat. Appln. KOKAI Publication No. (hereinafter referred to as "JP-A-") 5-313322.
Further, it is described in, for example, JP-A-57-150845 and JP-A-59-170840 that the enhancement of the graininess of color image and the increase of sensitivity are attained by the use of a coupler which releases a competing compound, a development accelerator or a fogging agent by a coupling reaction with a developing agent in an oxidized form. Still further, it is described in, for example, JP-A-62-218962 and JP-A-63-202745 that the formation of color image, the increase of the density of dye formed from the coupler and the improvement or correction of the hue of the dye or another dye can be realized by releasing a dye or a dye precursor through a coupling reaction with a developing agent in an oxidized form.
As apparent from the above, couplers which release a photographically useful group contribute to the enhancement of color image quality and the increase of sensitivity. However, the coupling reaction of these couplers with a developing agent in an oxidized form leads to not only the release of PUG but also the formation of an azomethine dye, so that it is not rare that the color reproducibility of color image is unfavorably influenced, thereby becoming a major cause of the restraints on the general applicability, use amount, molecular design, etc. of such functional couplers.
As the means for overcoming these problems, the coupler (colorless compound-forming coupler) which can release PUG substantially without the formation of a dye by coupling with a developing agent in an oxidized form is described in, for example, Jpn. Pat. Appln. KOKOKU Publication No. (hereinafter referred to as JP-B-) 52-46817 and U.S. Pat. No. 4,315,070. Further, the coupler (outflow dye-forming coupler) which forms a dye simultaneously with the release of PUG by a coupling reaction with a developing agent in an oxidized form, this dye, however, outflowing into a processing solution during the photographic processing, is described in, for example, JP-B-1-52742, JP-A-4-356042 and JP-A-8-44011. However, the former colorless compound-forming coupler has drawbacks in that the coupling activity is low and that the stability of the coupler is poor. On the other hand, the latter outflow dye-forming coupler has the problem that the outflow dye contaminates the processing solution, this being unfavorable in these days in which the reduction of replenisher is being promoted in the processing.
Moreover, the method of utilizing a redox reaction with a developing agent in an oxidized form is known as means for releasing PUG without the formation of any dye. For example, this method comprises the use of DIR-hydroquinones as described in, for example, JP-A-49-129536 and U.S. Pat. No. 4,377,643; the use of DIR-aminophenols as described in JP-A-52-57828; the use of p-nitrobenzyl derivatives as described in, for example, European Patent (hereinafter referred to as "EP") No. 45,129; and the use of hydrazine derivatives as described in, for example, JP-A-8-211542. However, these redox compounds generally have drawbacks in that the stability against time thereof in the light-sensitive material is low and the release of PUG after the redox reaction is slow, as compared with those of the above functional couplers.
On the other hand, the scheme of releasing a photographically useful group, which is a dye, from a non-coupling site through a cyclization reaction which occurs subsequent to the coupling reaction between a coupler and a developing agent in an oxidized form is described in, for example, U.S. Pat. Nos. 3,443,940 and 3,751,406. However, in this scheme, not only is the cyclization product obtained after the cyclization reaction composed of a dye without exception but also problems are encountered such that (1) the scope of selection of photographically useful group which can be released is small and (2) a sequence of reactions including coupling.fwdarw.cyclization reaction.fwdarw.release of photographically useful group are not always rapid.